According to a new study from Ohio State University, coastal communities could lose up to 50 percent more of their fresh water supplies than previously thought as sea levels continue to rise . For the study, hydrologists simulated how saltwater will intrude into fresh water aquifers, based on predictions by the Intergovernmental Panel on Climate Change (IPCC), which has concluded that within the next 100 years, sea level could rise as much as 23 inches.

Prior to this study, scientists assumed that, as saltwater moved inland, it would penetrate underground only as far as it did above ground. However, this new research shows that when saltwater and fresh water meet, they mix in complex ways, depending on the texture of the sand along the coastline. In some cases, a zone of mixed, or brackish, water can extend 50 percent further inland underground than it does above ground . Like saltwater, brackish water is not safe to drink because it causes dehydration. According to the Untied States Geological Survey, about half the county gets its drinking water from groundwater.

Scientists have used the IPCC reports to draw maps of how the world's coastlines will change as waters rise and they have produced some of the most striking images of the potential consequences of climate change. Researchers would like to create similar maps that show how the water supply could be affected, but it is not an easy task since scientists do not know exactly where all of the world's fresh water is located nor how much there is.

The U.S. Court of Appeals denied the city of Portland's request to be exempt from a federal water-treatment rule that requires cities to address cryptosporidium risks from their water supplies. The court ruling will force Portland to erect a water treatment plant at the remote Bull Run watershed by 2014, in order to lower levels of cryptosporidium - a parasite which can seriously sicken people with weak immune systems and does not exist at high levels in Bull Run's naturally pure water.

The federal law also makes Portland protect or further treat water once it hits the city's five reservoirs. In order to comply with this regulation, the city of Portland could cover the now open reservoirs, close the reservoirs and build covered storage or add five "mini-treatment plants" at the reservoirs . It is estimated that implementing this rule could cost between $125 million to $350 million.

Portland, which filed the appeal along with New York, argued that the rule was flawed because the EPA did not sufficiently study its costs and benefits, use the best science to make the rule or respond adequately to public comments.

The Environmental Protection Agency has scheduled a meeting for Dec. 5 - 6 in Washington, DC, to discuss a federal rule on controlling microbial contaminants in drinking water. The meeting will be the third of 10 planned meetings under the Federal Advisory Committee Act to consider revisions to EPA's Total Coliform Rule (TCR). Total coliforms are a group of closely related bacteria that, while usually not harmful to humans, can indicate a water utility distribution system's vulnerability to more dangerous pathogens. The TCR, which was published in 1989, set both health goals and legal limits for the presence of total coliforms in drinking water. The rule applies to all public water systems and details the type and frequency of testing that water systems must undertake.

Topics of discussion at the December meeting will include: TCR rule objectives and how the TCR relates to other Safe Drinking Water Act regulations, TCR indicator framework, TCR implementation and compliance analysis, potential ways to revise the TCR and an assessment of the information on distribution system issues that may impact water quality.